Linearized engine for aircraft catapult



Sept. 29, 1959 D. B. DOOLITTLE ETAL 2,906,475

LINEARIZED ENGINE FOR AIRCRAFT CATAPULT Filed March 22, 1957 16Sheets-Sheet 1 I INVENTOR5 BY I D. B. DOOLITTLE ETAL 2,906,475

LINEARIZED ENGINE FOR AIRCRAFT CATAPULT Filed March 22, 1957 Sept. 29,1959 16 Sheets-Sheet 2 TL Q mwsmons 0170 4 3200212??? @Jmwme y/reafieyATTORNEY P 1959 D. B. DOOLITTLE ETAL 2,906,475

LINEARIZED ENGINE FOR AIRCRAFT CATAPULT Filed March 22, 1957 l6Sheets-Sheet 3 41 0 INTAKE 1N VENTORS ATTORNEY Sept. 29, 195 9 D. B.DOOLITTLE ETAL 2,

LINEARIZED ENGINE FOR AIRCRAFT CATAPULT Filed March 22, 1957 l6Sheets-$heet 4 [fife/77a? (Midas/26.12,

INVENTORS I ATTORNEY D. B. DOOLITTLE EI'AL LINEARIZED ENGINE FORAIRCRAFT CA'IAPULT Filed March 22, 1957 Sept. 29, 1959 16 Sheets-Sheet 5MQQ v NVENF RS Jana/0 B. $002215]? Jammie 6f keafzegl ATTORNEY p 1959 D.B. DOOLITTLE ETAL 2,906,475

3 LINEARIZED ENGINE FOR AIRCRAFT CATAPULT Filed March 22. 1957 16Sheets-Sheet 6 ATTORNEY Sept. 29, 195? D. B. DOOLITTLE ETAL 2,906,475

LINEARIZ ED ENGINE FOR AIRCRAFT CATAPULT- Filed March 22, 1957 l6Sheets-Sheet 7 M 0% m a 3 z 1 7 x Z in h ATTORNEY p 1959 D. B. DOOLITTLEElAL 2,906,475

LINEARIZED ENGINE FOR AIRCRAFT CATAPULT Filed March 22, 1957 16Sheets-She et s Sept. 29, 1959 D. B. DQOLITTLE ETAL LINEARIZED ENGINEFOR AIRCRAFT CATAPULT Filed March 22, 1957 16 Sheets-Sheet 1O ATTORNEYSept. 29, 1959 D. B. DOOLITTLE EIAL LINEARYIZED ENGINE FOR AIRCRAFTCATAPULT Filed March 22. 1957 16 Sheets-Sheet l1 ATTORNEY p 1959 D. B.DOOLITTLE ETAL 2,906,475

, LINEARIZED- ENGINE FOR AIRCRAFT CATAPULT Filed March 22. 1957 16Sheets-Sheet 12 INVENTORS .BY C a 4 ATTORNEY 16 Sheets-Sheet 15 ATTORNEYQ em 0% Q\ vQ00 60.0 8% GUN 000 one 600 8086 0869 D. B. DOOLITTLE ETTALua/200' ma/v! LINEARIZED ENGINE FOR AIRCRAFT CATAPULT Sept. 29, 1959Filed March 22, 1957 pt. 29, 1959 D. B. DOOLITTLE EI'AL 2,905,475

LINEARIZED ENGINE FOR AIRCRAFT CATAPULT Filed March 22, 1957 16Sheets-Sheet 14 1NVENTOR5 ATTORNEY NM ANQN NW4! ML 35 R Q BN vs 16Sheets-Sheet 15 INVENTORS ATTORNEY D. B. DOOLITTLE ETAL LINEARIZEDENGINE FOR AIRCRAFT CATAPULT Sept. 29, 1959 Filed March 22, 1957 Sept.29, 1959 D. B. DOOLITTLE EI'AL- V 2,906,475

LINEARIZED ENGINE FOR AIRCRAFT CATAPULT l6 Sheets-Shet 16 Filed March22, 1957 MUG operations.

2,906,475 LINEARIZED ENGINE FOR AIRCRAFT CATAPULT Donald B. Doolittle,Wilmington, and Sammie G. Keahey,

Newark, Del. Application March 22, 1957, Serial No. 648,486,

28 Claims. (Cl. 244-63) The present invention relates generally to alinearized engine of the compression and expansible chamber type adaptedto be powered with expansible power medium, such as developed frominternal combustion, steam, or compressed air, including means driven bysaid expansion of the power medium used. As an example, the driven meansmay be a cam to which the power of the expanding medium is transferredand the cam may in turn impart the power to a driven member toaccomplish work.

One specific object of the present invention is to provide a novelsystem for launching aircraft.

It is another object of the invention to provide a novel combination ofexpansible chamber forming elements, such as moving vanes adapted toform the side walls of the expansible chambers, which walls are movablelaterally by the opposed curved surfaces of an eliptical or .almondshaped cam traversable along a linear path.

Another object is to so arrange and so proportion the vanes, theexpansible chambers formed thereby, and the contours of the cam as tohave expanding pressures developed from combustion, steam or compressedfluids and to act directly on the cam surfaces, thus eliminating theneed of heavily loaded cam followers.

Another object is to so arrange and proportion the vanes and valvingthat the expansible medium may be used to assist in actuation of thevanes and thereby reduce the loading between the vanes and the cam.

Thus the thrust imparted to the cam by the power medium expanding in themovable walled chambers is developed by the differential in pressure onthe respective opposed curved forward and opposed curved aft portions orfaces of the cam. For example, as the cam is moved linearly, the chamberwalls opposite the respective opposed curved faces of the forwardportion of the cam are forced to retract into the body of the housing inwhich they are mounted, thus reducing the volume of the chamhers towardthe progressively higher portions of the respectively opposed curved camfaces and compressing the air in the chambers. When the center or highpoint cam faces are reached the power medium, such as steam, orcompressed air is injected or a compressed charge of fuel and air isignited to produce a relatively high pressure in the chambers on therespectively opposed curved aft faces of the cam, to thereby provide thethrust as will be described hereinafter in detail with reference to thedrawings.

Another object is to provide for favorable thrust performancecharacteristics of a linear type catapult, based on a given brake meaneifective pressure (B.M.E.P.), the

depth and the stroke of the chamber, and the number of cycles or camsections employed.

A still further object is to provide a housing with a centrallypositioned shuttle track above the cam or cam sections in the housing,and to further provide a novel shuttle for the track which is engageableby the cam or connected thereto to drive the same for aircraft launchingStill a further object is to provide a novel housing for 2,906,475Patented Sept. 29, 19 59 ICC the present novel engine, whereby the samemay be made in a unit building block system in which each portionthereof may be made up ofa machine casting or weldment containing allthe parts, valves and mechanism necessary for one chamber, so that aseries of these components may be fastened together for whatever lengthis desired. Such arrangement of components makes it possible to applymass production techniques in manufacture of such engines to provide foreconomy.

Yet another object is to provide a catapult comprising a linearizedsupercharged two-cycle engine utilizing cams and vanes in lieu ofpistons and cylinders. 1

A still further object is to provide an air and fuel charging system 7in combination with a system for supplying additional air under highpressure, to thereby supercharge the engine, and wherein the combinationof valving, supercharging pressure, expansion ratios and type of cyclemay be arranged to provide maximum power and efiiciency.

Yet still a further object is to so arrange the valving that the enginebe used to absorb high energies, such as to arrest high speed objects,such as an arresting gear for aircraft. a

With these and other objects in view which will become apparent as theinvention is fully understood, the same resides in the novelty ofconstruction, combination and arrangement of elements hereinafterdescribed in detail and distinctly set forth in the appended claims.

The description should be read in conjunction with the accompanyingdrawings, wherein:

Figure l is a broken perspective view partly in section of a singlecycle engine;

Figure 1 discloses a single cycle or single cam linear engine in a planview thereof with the shuttle and shuttle track removed to expose themovable vanes,chambers, fuel and ignition and cam with its vaneconnections;

Figure 2 is an enlarged top plan and longitudinal section of a few ofthe assembled internal combustion engine components, which when coupledtogether form the engine housing;

Figure 2 is a transverse sectional view'on section line 2*--2 of Figure'2, showing several of the components joined together;

Figure 3 discloses a detail of one arrangement for connecting a shuttlewith the bridle hook to the drive cam traversable below the same in thechambered power housing of Figures 1 and l Figures 4 and 5 arediagrammatic illustrations of the operation of an internal combustioncycle and ofa steam power cycle, respectively;

Figure 6 is a view taken on section line 66 of Figure 16; i

Figure 7 is a view taken on section line 77 of Figure l6;

Figure 8 is a section view taken on section line 88 of Figure 16; I

Figure 9 is a view taken on the section line 99 of Figure 16;

Figure 10 is a diagrammatic representation of a fuel and air supplysystem with the exhaust manifold arrangement from the chambers on eachside of the cam means;

Figure 11 is a cut away perspective view of a second embodiment of theinvention with the shuttle in position for towing an aircraft;

Figure 12 is an enlarged view of a cut away portion of .Figure 11 withthe shuttle pulled apart to uncover the expansion chambers andassociated working elements thereof;

Figure 13 is a cross section view of the starting end of Figure 15 is adiagrammatic top view of the engine showing the shuttle, tandem cams,side expansion chambers, braking probe and a starter mechanism;

Figure 16 is a diagrammatic plan view of a cam and indicating inparticular the disposition of the intake and exhaust valves;

Figure 17 is a top plan view of the shuttle in accordance with asatisfactory structural embodiment thereof;

Figure 18 is a vertical longitudinal section of the shuttle;

Figure 19 is a vertical section in the plane of line 1919 of Figure 18;

Figure 20 is a transverse sectional view showing the shuttle in the camhousing;

Figure 21 is a transverse section showing the disposition of the trackslot sealing strip;

Figure 22 is a cross section view taken of the stroke area of the engineas observed in the plane of line 22-22 on Figure 34;

Figure 23 is a diagrammatic illustration of the starting operation;

Figure 24 is a diagrammatic illustration of the braking operation;

Figure 25 is a graphic illustration of the performance characteristicsof the second embodiment of the invention;

Figure 26 is a third embodiment of the invention illustrating in cutawayperspective a cam and vane steam type engine;

Figure 27 is a vertical transverse sectional view in the plane of line27-27 on Figure 26;

Figure 28 is a top plan view as observed in the plane of broken line2828 on Figure 27;

Figure 29 is a diagrammatic illustration of the steam supply system andexhaust manifold;

Figure 30 is a graphic illustration of the performance characteristicsof the steam type engine;

Figure 31 is illustrative of a slotless catapult for the engines ofeither the combustion or steam type;

Figure 32 is a block diagram arrangement of one form of ignition controlsystem;

Figure 33 is a block diagram for a second form of ignition controlsystem; incorporating preventive over speed control;

Figure 34 is a diagrammatic view of the general arrangement of thelaunching means.

Generally the present invention comprises an elongated housing A formedof a plurality of preformed units B, see Figures 1 2 and 2 together inalignment in spaced parallel rows C and D along each side of the housingA, which includes top and bottom plates E and F. Each unit of theinternal combustion type, shown in Figures 1, 2 and 2 includes a dome orhead 15 which mounts the fuel injector 16 and the ignition means 17 withrectangular recesses 18 and 19 and a gas scavenging duct 19 formed inthe unit casting on each side of the dome 15 and in each of which aremovably mounted walls or vanes 20 adapted to extend laterally into thespace between the rows C and D. These walls cooperate to form expansionchambers 22 when a curved side face of a cam G moves along between therows C and D and engages the free ends 23 of the walls or vanes 20. Theinner edges of the vanes 20 are maintained in close contact with thelateral walls of cam G and suitable means are provided for returningsuch vanes after having been pushed laterally outwardly by cam G, andwhich may comprise a groove 20 in each opposite side of the cam (Figures1 12 and 28), in which are disposed sliding members 20,

The cam G may be formed for single cycle operation O The units aresecured as in Figures 1 and 1 or for multiple cycle operation asillustrated in Figure 15, hereafter referred to in detail. The singlecycle cam comprises opposed curved faces 24 and 25 (Figure 1) to providean elliptical formation, whereby there is a central high portion on eachside tapering or falling off progressively to a final absolute lowportion, which provides for intake and exhaust of one cycle and thenintake for the start of the next cycle. These progressive high to lowportions provide for the thrust transfer to the cam, as illustrated inFigure 4, for internal combustion operation. For example, the cam whenpositioned as in Figure 1 or in Figure 4 creates chambers 22 22 22 22 2222 22 22 22 22 22, and 22 At the start of a cycle the cam G is given aforward boost as will be explained fully hereinafter in connection withFigure 15 in connection with the tandem embodiment of cams. Each cam isformed at its narrow or low point end with aligned groups of air inletchannels 27, an air intake manifold 27, and controlled exhaust channels28 to exhaust ports 28*, see Figures 2 and 12, while the cam face of thecentral high point is solid, see sectional Figures 6, 7, 8 and 9 forexamples of the respective low and high points. Fuel is supplied throughfuel intake manifold 38 to injectors 16, see Figure 10. I

The shuttle H (Figures 15, 17, 18, 19 and 20), may comprise a bridlehook 29, a dolly 30 with guide wheels 31 for engagement with theunderside of track rails 32 mounted in the top plate E of the housing A(Figure 20). The dolly 30 may be coupled to the cam G by suitablereleasable means pivotally connected to cam G by a slotted lug 33 and apin 34 as shown in Figure 3, or it may be pushed by the front portion ofthe cam, if desired. Thus basically the operation of the engine resultsin forward travel of the cam G with the shuttle H and air is broughtinto the opposed aligned chambers 22 22 22 22 and 22 through said supercharging channels 27. The air is compressed by the configuration of thecam faces 24 and 25, which cam faces also retract the walls or vanes 20.Fuel is injected to the compressed air in the chamber 22 and the same isignited by the spark plug 17. As the cam continues to move forward theignited gases expand in chambers 22', 22 22 22 22 and 22 Then the cam Gand the shuttle H are moved forward by the ignition of the gases, andgases are discharged through exhaust ports 28 as the vanes 20 move toopen same in the housing A for exhausting the chambers at the afterreduced portions of the cam.

This engine may be supercharged by the supply of high pressure air intothe compression chambers during the cam stroke, see Figure 10, for thegeneral diagrammatic illustration of the fuel system.

The system comprises a fuel pump 36 having a connection 37 with a fuelsupply, and which pump feeds the fuel manifold 38 to the fuel injectors16, an air supply 39, to an air compressor 40 connected to the airsupply manifold 27 and leading into the respective chambers through theintake channels 27 therefor, see Figure 2 This is a dual supply and isduplicated on the opposite side of the housing A to the chambers on saidopposite side.

The foregoing description has illustrated and described a single cycleor single cam linear engine, but it may be preferable to use multipletandem cams, to thereby provide a two or more cycle linear engine ashereinafter described in connection with a second embodiment of thisinvention. Referring specifically to Figures 11, 12 and 13, there isshown a smiliar housing A formed of units B secured together in spacedparallel rows C and D' along each side of the housing as in embodimentone. The housing A of the second embodiment also includes the top plateE and bottom plate or base F and includes the dome or heads 15', fuelinjectors 16', ignition means 17 with the vane recesses 18', thescavenger duct 19, and the chamber forming vanes 20 as described'inembodiment one. The principal difference of embodiment two resides inthe cam G which comprises, for example, a two or more cycle arrangement,formed by a number of cams, G G G and G used in tandem. -Each chamberwill deliver as many power strokes as there are cams; The structuralfeatures of the housing and the component units and the working partstherein of the second embodiment are substantially identical toembodiment one. Therefore a detailed description of the differentstructural features only, such as the tandem cam means and the operationplus the water brake probe P engageable in a water cylinder, thestarting means S, and a few additional details should suflice todescribe the second embodiment to others skilled in the art, see Figure15 for a general layout of this embodiment.

In embodiment two, the housing A is comprised of a greater number ofunits B joined together and includes the tandem cams G G G and G asshown in Figures 11, 12 and 15. Also, the shuttle H is basically thesame except that it is mounted to travel along the track in the topplate E over a sealing strip R, which normally seals the track space andprotects the combustion chamber below the track from foreign matter orthe like. This strip is not subjected to any pressure, see Figures 18 to22, wherein it will be seen that strip R is normally snapped intogrooves 32 in track rail 32 and the shuttle H is provided with a channel30 which receives and temporarily retracts the strip R from its normalposition in Figure 21, and replaces same after shuttle has passed.

The general operation of the tandem cam equipped engine is much like thesingle cam engine. Air from the supercharge manifold 27*, Figure 10, issupplied to the engine chamber 22' through ports 27 in the low'part ofthe cams G, G etc. The rising part of the cams have no ports. The air inthe chambers 22' .is compressed as the rising part of the cam passes,and at approximately top dead center, see Figure 1 fuel injection isstarted through fuel intake manifold 38 (Figure and ignition is appliedto igniting means 16 by way of ignition switches SW energized from ahigh voltage source or spark transformer, see Figure 32.

During the passage of the gradually falling part of the cam, which alsocontains no ports, burning continues until the excess of air is used up.The fuel injection rate may be so arranged and timed that a burning atthe constant pressure of a semi-diesel type cycle is maintained. It isbelieved that this type of cycle will result invery high mean effectivepressures and reliable firing without preheating.

After burning or ignition is complete, the hot gases are expanded in thetrailing chambers 22' to 22 until the low part of the cam is reached,see Figure 4. Then the exhaust ports 23 are uncovered as the low pointis reached, to thereby allow the expanded gas to escape. As thesechambers 22"22 approach supercharge pressure, intake ports 27 in the lowpart of the cam are uncovered and, with both intake and exhaust ports28' and 27' respectively open, these chambers are scavenged of burnedgas. As the cam continues to move, the intake ports remain open, but theexhaust ports will be closed, said intake ports remaining open to permita new charge of air to be forced into the next chambers for the next cyce. I

The time and the maximum velocity of the catapult determine the lengthof the straight port section between cams G, G G and G The starting andstopping operations of the linear engine or catapult are illustrated inFigure 13 and in the starting operation the following actions takeplace. Air

pressure is admitted into chamber 50 through the line 50*".

switches, similar to those used for ignition and fuel injection,determines the proper timing and ports for com 7 pressed air to passthrough line 51 and into the chamber Valving operated by the slidingcylinder wall 51 This causes the piston 52 to move back into chamber52*, thus opening the valve 53. Air displaced by the movement of piston52 in chamber 52 is discharged to atmosphere through the line 53 Whenthe valve 53 is opened in this manner, the compressed air in chamber 50is allowed to enter the chamber 54. The chamber 54 is the normalcompression cylinder for the catapult, and when compressed air isadmitted as above on the down side of the cam G, it is propelledforwardly to start the compression and ignition operation.

In the braking operation of the linear engine or cata pult, air at apredetermined pressure is induced into the chamber 50 through the line50, which holds the valve 53 closed. No pressure is induced in chamber51 in this case. As the cam G enters the braking area, it con tinues tocompress air in the compressing chamber or cylinder 54 because of itsconfiguration and forward motion. When the air in chamber 54 iscompressed to a higher p.s.i. than the predetermined pressure in chamber.50, the valve 53 is forced open and the higher pressure is transmittedback through chamber 50 and line 50 to the main accumulator 74. The workrequired to do this results in a braking force upon the main cam G andthereby applies the deceleration loads required to stop the forwardmotion of the cam G. It is at this point to be noted that'identicalcomponents comprise both the starting and the braking areas,thus it is aselective process as to which end of the stroke is used for starting andwhich for braking, which results in a unidirectional device. It is to befurther noted that no ignition of fuel injection is provided in thestarting and braking areas.

At the end of'the stroke, a similar action stops the shuttle and thecams in the samemanner as the original start. If necessary, internalcombustion may be used to speed the return stroke, but because theporting will be in reverse, the combustion will be without supercharge.At battery, the starting system stops the shuttle and cams.

Timing is accomplished through the vane actuated ignition switches SWfor each engine chamber, as it reaches near top dead center, see Figures1 and 32. The actual ignition will be accomplished by a spark plug and ahigh intensity ignition system, one form being illustrated by blockdiagram in Figure 32. The fuel injection as above explained is byinjectors 16 using a high pressure fuel pump and high pressure air foratomization and the fuel is timed by a valve actuated by the moving vanenear top dead center of the cam high point as previously explained.

Also in Figure 32 is illustrated a speed sensing circuit 55 tied intothe ignition system 56 to preventa runaway shot. For example, the speedmay be preset at 57 and when the preset speed is exceeded, the controlphase 57 varies with the actual velocity phase and an error signal isgenerated in the error measurement means, which will cut off the sparkand stop the ignition operation.

In Figure 33 is disclosed a second arrangement of overshot control usinga motor driven switch 60 and actual velocity stroke responsive means 61,a pre-set velocity stroke means 62, each leading to a two phase motor orthe like 63, which when the phases are alike remains inoperative, butwhen they become out of phase will give an output by shaft 64 to drivean overspeed motor to cut off the drive to the motor driven ignitionswitch 69. Such follow up and error control systems are well known inthe remote control of valves, motors and the like and therefore theactual structural details of the units in system are not believednecessary.

A third embodiment of the invention is disclosed in Figures 26, 27, and28, which is of the same general construction as the above describedsecond embodiment, but wherein a power medium in the form of steam isutilized instead of the combustible medium utilized in the secondembodiment. a

The cam G and variable capacity chambers 22 correspond to that of thesecond embodiment, and the essential difference between the structure ofthe second embodiment and that of the third embodiment is in theprovision of a pair of steam manifolds 65 (Figure 26), intake steamports 66, exhaust ports 67 and inlet port control valves 68 which areoperable by earns 69 projecting from opposite sides of the chambercontrol main cam G and each side of the housing is provided with a valvelock mechanism 70. The chamber forming vanes in this embodiment aredesignated 20A.

A safety feature is involved in this steam type catapult which preventsrunaway catapult shots by cutting off the steam supply to eachindividual unit. This cut-off at each unit reduces the time lag to stopthe cam to practically nothing as it is immediately adjacent to theexpansion chamber.

With reference to Figure 27 in this connection, it will be seen that thevalve 68 is fixed to a cylindrical member 68- which is backed by aspring 68* and through which the valve stem 68 has free slidingmovement. The member 68 is provided with a slot 68' and a lock pin 68 isprovided for alternate positions, one of which is as shown in Figure 27and the other of which is in the slot 68 When the pin 68 is in slot 68stem 68 can be depressed by cam 69 without opening of valve 68. If thevalve does not open, no steam is injected and the shuttle carrying camis no longer accelerated.

The rotation of the lock pin is accomplished externally of the engine bymultiple interconnected valve intake lock arms which are actuated when astop is desired.

The diagrammatic view in Figure 29 corresponds to that of Figure 10, butdiscloses the system wherein steam is utilized as the power medium.

The diagrammatic illustration in Figure 5 is similar to that in Figure4, the former of which relates to the internal combustion engine and thelatter of which relates to the steam engine and from which figures itwill be apparent that the operation is substantially the same in the twoforms.

In Figure 14 is disclosed a safety feature for the catapult, which is ameans to prevent runaway catapult shots by cutting off the intake airsupply necessary for combustion.

As indicated, such means comprises an accumulator or manifold 74 fromwhich the intake air supply enters the intake control valve 74 throughthe port 75.

The intake air supply in the manifold accumulator 74 enters the intakecontrol valve 74 of the unit through port 75; located in port 75 is aremotely operated lever 77 to open and close valve 74. A valve of thistype is located in each port 75 for the full length of the catapult withthe exception of the starting and braking areas at each end. Thesevalves are normally open; however, in the event an emergency stop isrequired, they are all closed remotely by lever 77. This cuts off thesupply of air required for combustion. Without the complete combustioncycle, the cam is no longer accelerated and comes to a halt. Thisfeature is also shown on Figure 22. When this is done the cam may beused to arrest an object such as aircraft engaged with the shuttle 80,see Figure 31.

Super charged air supply Super charged air is supplied through themanifold accumulator 74 as shown on Figure 14 and passes through port 75(Figure 14). It is retained in the manifold by the valves 76. Anactuating surface cam 54 is along the center line of the main cam body Gthat forces the valves open when it is in contact with the actuatingstem 76 of the valve 76. This allows the supercharged air to pass intothe intake ports on the main cam G, only at the points where the maincam G is in a position to use the air. All valves ahead of and behindthe main cam G remain closed and prevent leakage of the air over theentire length of the catapult. Each unit assembly houses one valve sothat each unit functions independently of the others.

In Figures 23 and 24 the starting and braking actions respectively arediagrammatically illustrated, and from the legends and explanatory noteson said figures, such starting and braking actions are believed to beclear.

In Figure 25 is graphically illustrated the performance of the internalcombustion type catapult in accordance with the second embodiment of theinvention.

In Figure 30 is graphically illustrated the performance of the steamtype catapult in accordance with the third embodiment of the invention.

In Figure 31 is disclosed a catapult which may be either of the internalcombustion or steam type, and may be of the same construction ashereinbefore described with the exception that the housing A is notprovided with the shuttle receiving slot which may be found advantageousin the exclusion of weather elements to the mechanism within thehousing.

Accordingly a cable 78 has opposite ends thereof connected to oppositeends of the cam G, and the cable is disposed around sheaves 79 mountedon a suitable surface, and a bridle engageable shuttle 80 is secured toa longitudinal reach 81 of the cable, which is disposed in spacedparallel relation to the housing A In Figure 34 is disclosed the generalarrangement of the engine, and wherein each end of the housing A isprovided with a braking and starting area a and a, and wherein themechanisms of Figures 13, 14 and 22 are disposed.

As indicated, the launching stroke is in the direction of arrow a butsince the cam may be power driven in its return from a final launchingposition, the starting and braking means are preferably disposed at eachend of the housing.

While the invention has been disclosed in accordance with certainspecific structural embodiments thereof, such are to be considered asillustrative only and not restrictive, the scope of the invention beingdefined in the subjoined claims.

What is claimed is:

1. A linear engine comprising an elongated housing, said housing beingdivided into chambers adapted to receive air and fuel from an air intakemanifold and a fuel intake manifold, intake ports and exhaust ports foreach chamber, an igniting member and a fuel injector nozzle in eachchamber, each of said chambers having walls laterally movable inrecesses formed in the housing, a cam means linearly movable along thehousing, and means responsive to the movement of said cam means forcontrolling the air and fuel intake parts, ignition, compression and theports for exhaust of gases from said chambers, and means driven by saidcam.

. 2. The liner engine described in claim 1, wherein the cam means isformed with a solid high portion and two low portions, one at each endprogressively falling from said high portion, said low portions eachhaving and exhaust openings arranged therein for cooperation with thefiring, compression and exhaust strokes of the cam as it traverses thesaid housing.

3. The linear engine described in claim 1, wherein the said cam means iscomprised of two or more cams in tandem, to thereby provide at least atwo cycle engine.

4. The linear engine described in claim 1, wherein the said cam drivenmeans comprises a track guided shuttle with a bridle hook.

5. The linear engine described in claim 1, wherein the said housing isformed with a central elongated space with said chambers being alignedalong each side thereof, and a guide way formed along the inner face ofthe said spaced apart chamber walls adapted to receive a projected partof the said cam means as the same is propelled along the same bycompressive forces resulting from the expansion of gases in the adjacentchambers.

